The effects of development and regression of atherosclerosis on the hemodynamics of the aorta and leg arteries will be studied in two species of monkey and in man. Non-invasive and invasive techniques will be used in the monkey studies; and non-invasive techniques in man to obtain pulse transit times, velocities, and frequency components of the cardiac ejection as it travels down the aorta and leg arteries. These data will be correlated with anatomical and biochemical data obtained at critical points in the study. These studies should provide a link between physiology and pathology in artherosclerosis and it may also lead to a non-invasive method of evaluating artherosclerosis in man.